Fernando Rodney has been absolutely lights out this season for the Rays. That means he'll probably be completely awful next season.

OK, that's terrible logic. But it's hard to explain Rodney's sudden turnaround at age 35, and in general, it's even harder to pinpoint exactly the type of production you're going to see from certain relievers each season. Rodney's historic season serves as the latest proof.

Rodney is on the cusp of finishing the year with the lowest single-season ERA in baseball history (for a pitcher with at least 50 innings). Entering Tuesday's action, the Rays closer has allowed just five runs all season in 74 1/3 innings, good enough for a 0.61 ERA. That matches Dennis Eckersley's 1990 mark, which Eck accomplished in 73 1/3 innings.

Rodney's dominance, while insanely impressive, is even more shocking when you consider the right-hander's recent history before this year. Here's a glimpse of the veteran's career numbers, which are pretty pedestrian for the most part. Until 2012.

Year

ERA (IP)

WHIP

Saves

K/9

2002

6.00 (18)

1.94

0

5

2003

6.07 (29.2)

1.75

3

10

2005

2.86 (44)

1.27

9

8.6

2006

3.52 (71.2)

1.19

7

8.2

2007

4.26 (50.2)

1.32

1

9.6

2008

4.91 (40.1)

1.59

13

10.9

2009

4.40 (75.2)

1.47

37

7.3

2010

4.24 (68)

1.54

14

7.0

2011

4.50 (32)

1.69

3

7.3

2012

0.61 (74.1)

0.78

47

9.2

Total

3.75 (504.1)

1.36

134

8.4

Entering the year, Rodney was essentially one of those guys whose ERA and WHIP was never going to be anything to write home about, but who had the potential to rack up some cheap saves for your fantasy squad if someone got hurt. Kyle Farnsworth did get hurt, allowing Rodney the opportunity to close, but the 35-year-old's effectiveness has gone beyond just putting up numbers in the saves column.

Adding to the apparent oddity is that all of this season's production comes at a bargain price for the Rays, who signed the righty for $1.75 million and a $2.5 million 2013 club option after his two subpar seasons with the Angels. That just goes to show that the best value when it comes to bullpen arms often comes from unexpected sources.

Sure, you've got some usual suspects you can count on to post solid numbers. Typically, that conversation begins and ends with Mariano Rivera, who unforuntately couldn't treat us to another dominant season this year because of an ACL injury. But we've seen some strange things in recent years that make you question whether or not it's ever a smart decision to throw big money at relievers based on their resume to date. Instead, it's more and more obvious that the wise route is to build through one's farm system, with low-risk, veteran pieces then rounding out the unit.

Rodney's stellar campaign is Exhibit A of why constructing a bullpen is often the most agonizing task a general manager faces. Relievers — especially those outside of the closer's role — not only don't jump off the page to the casual fan, but they're so prone to having varying degress of success — or lack thereof.

Examples of such unpredictability is evident in all corners of Major League Baseball, but in addition to Rodney, let's hone in on the Reds' bullpen, which boasts the league's best ERA. Cincy has gotten meaningful innings from the likes of Alfredo Simon, Jose Arredondo and Jonathan Broxton, all of whom endured struggles at one point or another before joining forces for Dusty Baker's team.

Or how about Baltimore's Jim Johnson? Sure, he was solid in 69 appearances for the O's last season, but it was once hard to imagine him becoming the major league saves leader just three years after posting an ERA north of 4.00 in 70 innings.

The street goes both ways, though. John Axford and Heath Bell are both respected closers who have been ousted from their ninth-inning duties in 2012 due to a sudden lack of effectiveness. That's not to say we should write them off completely — in fact, history shows quite the opposite. But their failures further magnify the wildness that is major league bullpens.

Rodney will enter next season at age 36, and on the heels of one of the most impressive relief seasons in MLB history. What will he have lined up for an encore? That's anyone's guess. Just understand that the Rays closer isn't alone when it comes to throwing us for a loop, even if he did take unexpected turnarounds to a whole new level.